The subject matter disclosed herein relates to organic photodiode detectors.
Organic photodiode (OPD) detectors are used in a variety of imaging contexts (e.g., molecular and optical imaging systems). For example, OPD detectors may be used in cameras and medical imaging applications such as computed tomography, positron emission tomography, magnetic resonance imaging, and many others. In such systems, radiation (e.g., UV light, infra-red light, X-ray, etc.) generally impinges upon an array of radiation detector elements of the OPD detector that generates readable signals in response to the impinging radiation. In certain detectors, a scintillator converts the radiation to lower energy optical photons suitable for detection by the provided photodetection elements. Each of the detector elements then produces a separate electrical signal indicative of the amount of radiation at the particular location of the element. The electrical signals are collected, digitized and transmitted to a data processing system for analysis and further processing to reconstruct an image.
Generally, the OPD detectors are manufactured by non-selectively coating one or more OPD layers onto a thin film transistor (TFT) array, resulting in a continuous OPD layer. As such, pixels within the TFT array are linked to each other by the OPD layer. This may lower detector performance and reliability. For example, because of the continuous OPD layer over scan lines and data lines, capacitance loading to data and/or scan lines of the TFT array may be increased. Increased capacitance loading to data and/or scan lines may be undesirable, causing increased electronic noise, reduced image quality. Moreover, multiple pixels may be affected by diffusion of environmental components (e.g., moisture, air, oxygen, etc.). In addition, the manner in which the OPD layers are deposited onto the TFT array results in peripheral areas of the OPD detector (e.g., areas outside the TFT array) to also be coated. As such, the excess coating may need to be removed to expose the peripheral areas (e.g., interconnection layers). Removal of the excess OPD coating in the peripheral areas may damage the OPD layers on the TFT array. Accordingly, a need exists to develop OPD detectors having patterned OPD layers that isolate each individual pixel within the TFT array.